- 根目录:
- net
- sunrpc
- auth_gss
- gss_krb5_crypto.c
/*
* linux/net/sunrpc/gss_krb5_crypto.c
*
* Copyright (c) 2000-2008 The Regents of the University of Michigan.
* All rights reserved.
*
* Andy Adamson <andros@umich.edu>
* Bruce Fields <bfields@umich.edu>
*/
/*
* Copyright (C) 1998 by the FundsXpress, INC.
*
* All rights reserved.
*
* Export of this software from the United States of America may require
* a specific license from the United States Government. It is the
* responsibility of any person or organization contemplating export to
* obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of FundsXpress. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. FundsXpress makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#include <linux/err.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/random.h>
#include <linux/sunrpc/gss_krb5.h>
#include <linux/sunrpc/xdr.h>
#ifdef RPC_DEBUG
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
u32
krb5_encrypt(
struct crypto_blkcipher *tfm,
void * iv,
void * in,
void * out,
int length)
{
u32 ret = -EINVAL;
struct scatterlist sg[1];
u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0};
struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
if (length % crypto_blkcipher_blocksize(tfm) != 0)
goto out;
if (crypto_blkcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
dprintk("RPC: gss_k5encrypt: tfm iv size too large %d\n",
crypto_blkcipher_ivsize(tfm));
goto out;
}
if (iv)
memcpy(local_iv, iv, crypto_blkcipher_ivsize(tfm));
memcpy(out, in, length);
sg_init_one(sg, out, length);
ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, length);
out:
dprintk("RPC: krb5_encrypt returns %d\n", ret);
return ret;
}
u32
krb5_decrypt(
struct crypto_blkcipher *tfm,
void * iv,
void * in,
void * out,
int length)
{
u32 ret = -EINVAL;
struct scatterlist sg[1];
u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0};
struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
if (length % crypto_blkcipher_blocksize(tfm) != 0)
goto out;
if (crypto_blkcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
dprintk("RPC: gss_k5decrypt: tfm iv size too large %d\n",
crypto_blkcipher_ivsize(tfm));
goto out;
}
if (iv)
memcpy(local_iv,iv, crypto_blkcipher_ivsize(tfm));
memcpy(out, in, length);
sg_init_one(sg, out, length);
ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, length);
out:
dprintk("RPC: gss_k5decrypt returns %d\n",ret);
return ret;
}
static int
checksummer(struct scatterlist *sg, void *data)
{
struct hash_desc *desc = data;
return crypto_hash_update(desc, sg, sg->length);
}
static int
arcfour_hmac_md5_usage_to_salt(unsigned int usage, u8 salt[4])
{
unsigned int ms_usage;
switch (usage) {
case KG_USAGE_SIGN:
ms_usage = 15;
break;
case KG_USAGE_SEAL:
ms_usage = 13;
break;
default:
return -EINVAL;
}
salt[0] = (ms_usage >> 0) & 0xff;
salt[1] = (ms_usage >> 8) & 0xff;
salt[2] = (ms_usage >> 16) & 0xff;
salt[3] = (ms_usage >> 24) & 0xff;
return 0;
}
static u32
make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen,
struct xdr_buf *body, int body_offset, u8 *cksumkey,
unsigned int usage, struct xdr_netobj *cksumout)
{
struct hash_desc desc;
struct scatterlist sg[1];
int err;
u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
u8 rc4salt[4];
struct crypto_hash *md5;
struct crypto_hash *hmac_md5;
if (cksumkey == NULL)
return GSS_S_FAILURE;
if (cksumout->len < kctx->gk5e->cksumlength) {
dprintk("%s: checksum buffer length, %u, too small for %s\n",
__func__, cksumout->len, kctx->gk5e->name);
return GSS_S_FAILURE;
}
if (arcfour_hmac_md5_usage_to_salt(usage, rc4salt)) {
dprintk("%s: invalid usage value %u\n", __func__, usage);
return GSS_S_FAILURE;
}
md5 = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(md5))
return GSS_S_FAILURE;
hmac_md5 = crypto_alloc_hash(kctx->gk5e->cksum_name, 0,
CRYPTO_ALG_ASYNC);
if (IS_ERR(hmac_md5)) {
crypto_free_hash(md5);
return GSS_S_FAILURE;
}
desc.tfm = md5;
desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
err = crypto_hash_init(&desc);
if (err)
goto out;
sg_init_one(sg, rc4salt, 4);
err = crypto_hash_update(&desc, sg, 4);
if (err)
goto out;
sg_init_one(sg, header, hdrlen);
err = crypto_hash_update(&desc, sg, hdrlen);
if (err)
goto out;
err = xdr_process_buf(body, body_offset, body->len - body_offset,
checksummer, &desc);
if (err)
goto out;
err = crypto_hash_final(&desc, checksumdata);
if (err)
goto out;
desc.tfm = hmac_md5;
desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
err = crypto_hash_init(&desc);
if (err)
goto out;
err = crypto_hash_setkey(hmac_md5, cksumkey, kctx->gk5e->keylength);
if (err)
goto out;
sg_init_one(sg, checksumdata, crypto_hash_digestsize(md5));
err = crypto_hash_digest(&desc, sg, crypto_hash_digestsize(md5),
checksumdata);
if (err)
goto out;
memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
cksumout->len = kctx->gk5e->cksumlength;
out:
crypto_free_hash(md5);
crypto_free_hash(hmac_md5);
return err ? GSS_S_FAILURE : 0;
}
/*
* checksum the plaintext data and hdrlen bytes of the token header
* The checksum is performed over the first 8 bytes of the
* gss token header and then over the data body
*/
u32
make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen,
struct xdr_buf *body, int body_offset, u8 *cksumkey,
unsigned int usage, struct xdr_netobj *cksumout)
{
struct hash_desc desc;
struct scatterlist sg[1];
int err;
u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
unsigned int checksumlen;
if (kctx->gk5e->ctype == CKSUMTYPE_HMAC_MD5_ARCFOUR)
return make_checksum_hmac_md5(kctx, header, hdrlen,
body, body_offset,
cksumkey, usage, cksumout);
if (cksumout->len < kctx->gk5e->cksumlength) {
dprintk("%s: checksum buffer length, %u, too small for %s\n",
__func__, cksumout->len, kctx->gk5e->name);
return GSS_S_FAILURE;
}
desc.tfm = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(desc.tfm))
return GSS_S_FAILURE;
desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
checksumlen = crypto_hash_digestsize(desc.tfm);
if (cksumkey != NULL) {
err = crypto_hash_setkey(desc.tfm, cksumkey,
kctx->gk5e->keylength);
if (err)
goto out;
}
err = crypto_hash_init(&desc);
if (err)
goto out;
sg_init_one(sg, header, hdrlen);
err = crypto_hash_update(&desc, sg, hdrlen);
if (err)
goto out;
err = xdr_process_buf(body, body_offset, body->len - body_offset,
checksummer, &desc);
if (err)
goto out;
err = crypto_hash_final(&desc, checksumdata);
if (err)
goto out;
switch (kctx->gk5e->ctype) {
case CKSUMTYPE_RSA_MD5:
err = kctx->gk5e->encrypt(kctx->seq, NULL, checksumdata,
checksumdata, checksumlen);
if (err)
goto out;
memcpy(cksumout->data,
checksumdata + checksumlen - kctx->gk5e->cksumlength,
kctx->gk5e->cksumlength);
break;
case CKSUMTYPE_HMAC_SHA1_DES3:
memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
break;
default:
BUG();
break;
}
cksumout->len = kctx->gk5e->cksumlength;
out:
crypto_free_hash(desc.tfm);
return err ? GSS_S_FAILURE : 0;
}
/*
* checksum the plaintext data and hdrlen bytes of the token header
* Per rfc4121, sec. 4.2.4, the checksum is performed over the data
* body then over the first 16 octets of the MIC token
* Inclusion of the header data in the calculation of the
* checksum is optional.
*/
u32
make_checksum_v2(struct krb5_ctx *kctx, char *header, int hdrlen,
struct xdr_buf *body, int body_offset, u8 *cksumkey,
unsigned int usage, struct xdr_netobj *cksumout)
{
struct hash_desc desc;
struct scatterlist sg[1];
int err;
u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN];
unsigned int checksumlen;
if (kctx->gk5e->keyed_cksum == 0) {
dprintk("%s: expected keyed hash for %s\n",
__func__, kctx->gk5e->name);
return GSS_S_FAILURE;
}
if (cksumkey == NULL) {
dprintk("%s: no key supplied for %s\n",
__func__, kctx->gk5e->name);
return GSS_S_FAILURE;
}
desc.tfm = crypto_alloc_hash(kctx->gk5e->cksum_name, 0,
CRYPTO_ALG_ASYNC);
if (IS_ERR(desc.tfm))
return GSS_S_FAILURE;
checksumlen = crypto_hash_digestsize(desc.tfm);
desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
err = crypto_hash_setkey(desc.tfm, cksumkey, kctx->gk5e->keylength);
if (err)
goto out;
err = crypto_hash_init(&desc);
if (err)
goto out;
err = xdr_process_buf(body, body_offset, body->len - body_offset,
checksummer, &desc);
if (err)
goto out;
if (header != NULL) {
sg_init_one(sg, header, hdrlen);
err = crypto_hash_update(&desc, sg, hdrlen);
if (err)
goto out;
}
err = crypto_hash_final(&desc, checksumdata);
if (err)
goto out;
cksumout->len = kctx->gk5e->cksumlength;
switch (kctx->gk5e->ctype) {
case CKSUMTYPE_HMAC_SHA1_96_AES128:
case CKSUMTYPE_HMAC_SHA1_96_AES256:
/* note that this truncates the hash */
memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
break;
default:
BUG();
break;
}
out:
crypto_free_hash(desc.tfm);
return err ? GSS_S_FAILURE : 0;
}
struct encryptor_desc {
u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
struct blkcipher_desc desc;
int pos;
struct xdr_buf *outbuf;
struct page **pages;
struct scatterlist infrags[4];
struct scatterlist outfrags[4];
int fragno;
int fraglen;
};
static int
encryptor(struct scatterlist *sg, void *data)
{
struct encryptor_desc *desc = data;
struct xdr_buf *outbuf = desc->outbuf;
struct page *in_page;
int thislen = desc->fraglen + sg->length;
int fraglen, ret;
int page_pos;
/* Worst case is 4 fragments: head, end of page 1, start
* of page 2, tail. Anything more is a bug. */
BUG_ON(desc->fragno > 3);
page_pos = desc->pos - outbuf->head[0].iov_len;
if (page_pos >= 0 && page_pos < outbuf->page_len) {
/* pages are not in place: */
int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
in_page = desc->pages[i];
} else {
in_page = sg_page(sg);
}
sg_set_page(&desc->infrags[desc->fragno], in_page, sg->length,
sg->offset);
sg_set_page(&desc->outfrags[desc->fragno], sg_page(sg), sg->length,
sg->offset);
desc->fragno++;
desc->fraglen += sg->length;
desc->pos += sg->length;
fraglen = thislen & (crypto_blkcipher_blocksize(desc->desc.tfm) - 1);
thislen -= fraglen;
if (thislen == 0)
return 0;
sg_mark_end(&desc->infrags[desc->fragno - 1]);
sg_mark_end(&desc->outfrags[desc->fragno - 1]);
ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
desc->infrags, thislen);
if (ret)
return ret;
sg_init_table(desc->infrags, 4);
sg_init_table(desc->outfrags, 4);
if (fraglen) {
sg_set_page(&desc->outfrags[0], sg_page(sg), fraglen,
sg->offset + sg->length - fraglen);
desc->infrags[0] = desc->outfrags[0];
sg_assign_page(&desc->infrags[0], in_page);
desc->fragno = 1;
desc->fraglen = fraglen;
} else {
desc->fragno = 0;
desc->fraglen = 0;
}
return 0;
}
int
gss_encrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
int offset, struct page **pages)
{
int ret;
struct encryptor_desc desc;
BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
memset(desc.iv, 0, sizeof(desc.iv));
desc.desc.tfm = tfm;
desc.desc.info = desc.iv;
desc.desc.flags = 0;
desc.pos = offset;
desc.outbuf = buf;
desc.pages = pages;
desc.fragno = 0;
desc.fraglen = 0;
sg_init_table(desc.infrags, 4);
sg_init_table(desc.outfrags, 4);
ret = xdr_process_buf(buf, offset, buf->len - offset, encryptor, &desc);
return ret;
}
struct decryptor_desc {
u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
struct blkcipher_desc desc;
struct scatterlist frags[4];
int fragno;
int fraglen;
};
static int
decryptor(struct scatterlist *sg, void *data)
{
struct decryptor_desc *desc = data;
int thislen = desc->fraglen + sg->length;
int fraglen, ret;
/* Worst case is 4 fragments: head, end of page 1, start
* of page 2, tail. Anything more is a bug. */
BUG_ON(desc->fragno > 3);
sg_set_page(&desc->frags[desc->fragno], sg_page(sg), sg->length,
sg->offset);
desc->fragno++;
desc->fraglen += sg->length;
fraglen = thislen & (crypto_blkcipher_blocksize(desc->desc.tfm) - 1);
thislen -= fraglen;
if (thislen == 0)
return 0;
sg_mark_end(&desc->frags[desc->fragno - 1]);
ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
desc->frags, thislen);
if (ret)
return ret;
sg_init_table(desc->frags, 4);
if (fraglen) {
sg_set_page(&desc->frags[0], sg_page(sg), fraglen,
sg->offset + sg->length - fraglen);
desc->fragno = 1;
desc->fraglen = fraglen;
} else {
desc->fragno = 0;
desc->fraglen = 0;
}
return 0;
}
int
gss_decrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
int offset)
{
struct decryptor_desc desc;
/* XXXJBF: */
BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
memset(desc.iv, 0, sizeof(desc.iv));
desc.desc.tfm = tfm;
desc.desc.info = desc.iv;
desc.desc.flags = 0;
desc.fragno = 0;
desc.fraglen = 0;
sg_init_table(desc.frags, 4);
return xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc);
}
/*
* This function makes the assumption that it was ultimately called
* from gss_wrap().
*
* The client auth_gss code moves any existing tail data into a
* separate page before calling gss_wrap.
* The server svcauth_gss code ensures that both the head and the
* tail have slack space of RPC_MAX_AUTH_SIZE before calling gss_wrap.
*
* Even with that guarantee, this function may be called more than
* once in the processing of gss_wrap(). The best we can do is
* verify at compile-time (see GSS_KRB5_SLACK_CHECK) that the
* largest expected shift will fit within RPC_MAX_AUTH_SIZE.
* At run-time we can verify that a single invocation of this
* function doesn't attempt to use more the RPC_MAX_AUTH_SIZE.
*/
int
xdr_extend_head(struct xdr_buf *buf, unsigned int base, unsigned int shiftlen)
{
u8 *p;
if (shiftlen == 0)
return 0;
BUILD_BUG_ON(GSS_KRB5_MAX_SLACK_NEEDED > RPC_MAX_AUTH_SIZE);
BUG_ON(shiftlen > RPC_MAX_AUTH_SIZE);
p = buf->head[0].iov_base + base;
memmove(p + shiftlen, p, buf->head[0].iov_len - base);
buf->head[0].iov_len += shiftlen;
buf->len += shiftlen;
return 0;
}
static u32
gss_krb5_cts_crypt(struct crypto_blkcipher *cipher, struct xdr_buf *buf,
u32 offset, u8 *iv, struct page **pages, int encrypt)
{
u32 ret;
struct scatterlist sg[1];
struct blkcipher_desc desc = { .tfm = cipher, .info = iv };
u8 data[GSS_KRB5_MAX_BLOCKSIZE * 2];
struct page **save_pages;
u32 len = buf->len - offset;
if (len > ARRAY_SIZE(data)) {
WARN_ON(0);
return -ENOMEM;
}
/*
* For encryption, we want to read from the cleartext
* page cache pages, and write the encrypted data to
* the supplied xdr_buf pages.
*/
save_pages = buf->pages;
if (encrypt)
buf->pages = pages;
ret = read_bytes_from_xdr_buf(buf, offset, data, len);
buf->pages = save_pages;
if (ret)
goto out;
sg_init_one(sg, data, len);
if (encrypt)
ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
else
ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, len);
if (ret)
goto out;
ret = write_bytes_to_xdr_buf(buf, offset, data, len);
out:
return ret;
}
u32
gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
struct xdr_buf *buf, int ec, struct page **pages)
{
u32 err;
struct xdr_netobj hmac;
u8 *cksumkey;
u8 *ecptr;
struct crypto_blkcipher *cipher, *aux_cipher;
int blocksize;
struct page **save_pages;
int nblocks, nbytes;
struct encryptor_desc desc;
u32 cbcbytes;
unsigned int usage;
if (kctx->initiate) {
cipher = kctx->initiator_enc;
aux_cipher = kctx->initiator_enc_aux;
cksumkey = kctx->initiator_integ;
usage = KG_USAGE_INITIATOR_SEAL;
} else {
cipher = kctx->acceptor_enc;
aux_cipher = kctx->acceptor_enc_aux;
cksumkey = kctx->acceptor_integ;
usage = KG_USAGE_ACCEPTOR_SEAL;
}
blocksize = crypto_blkcipher_blocksize(cipher);
/* hide the gss token header and insert the confounder */
offset += GSS_KRB5_TOK_HDR_LEN;
if (xdr_extend_head(buf, offset, kctx->gk5e->conflen))
return GSS_S_FAILURE;
gss_krb5_make_confounder(buf->head[0].iov_base + offset, kctx->gk5e->conflen);
offset -= GSS_KRB5_TOK_HDR_LEN;
if (buf->tail[0].iov_base != NULL) {
ecptr = buf->tail[0].iov_base + buf->tail[0].iov_len;
} else {
buf->tail[0].iov_base = buf->head[0].iov_base
+ buf->head[0].iov_len;
buf->tail[0].iov_len = 0;
ecptr = buf->tail[0].iov_base;
}
memset(ecptr, 'X', ec);
buf->tail[0].iov_len += ec;
buf->len += ec;
/* copy plaintext gss token header after filler (if any) */
memcpy(ecptr + ec, buf->head[0].iov_base + offset,
GSS_KRB5_TOK_HDR_LEN);
buf->tail[0].iov_len += GSS_KRB5_TOK_HDR_LEN;
buf->len += GSS_KRB5_TOK_HDR_LEN;
/* Do the HMAC */
hmac.len = GSS_KRB5_MAX_CKSUM_LEN;
hmac.data = buf->tail[0].iov_base + buf->tail[0].iov_len;
/*
* When we are called, pages points to the real page cache
* data -- which we can't go and encrypt! buf->pages points
* to scratch pages which we are going to send off to the
* client/server. Swap in the plaintext pages to calculate
* the hmac.
*/
save_pages = buf->pages;
buf->pages = pages;
err = make_checksum_v2(kctx, NULL, 0, buf,
offset + GSS_KRB5_TOK_HDR_LEN,
cksumkey, usage, &hmac);
buf->pages = save_pages;
if (err)
return GSS_S_FAILURE;
nbytes = buf->len - offset - GSS_KRB5_TOK_HDR_LEN;
nblocks = (nbytes + blocksize - 1) / blocksize;
cbcbytes = 0;
if (nblocks > 2)
cbcbytes = (nblocks - 2) * blocksize;
memset(desc.iv, 0, sizeof(desc.iv));
if (cbcbytes) {
desc.pos = offset + GSS_KRB5_TOK_HDR_LEN;
desc.fragno = 0;
desc.fraglen = 0;
desc.pages = pages;
desc.outbuf = buf;
desc.desc.info = desc.iv;
desc.desc.flags = 0;
desc.desc.tfm = aux_cipher;
sg_init_table(desc.infrags, 4);
sg_init_table(desc.outfrags, 4);
err = xdr_process_buf(buf, offset + GSS_KRB5_TOK_HDR_LEN,
cbcbytes, encryptor, &desc);
if (err)
goto out_err;
}
/* Make sure IV carries forward from any CBC results. */
err = gss_krb5_cts_crypt(cipher, buf,
offset + GSS_KRB5_TOK_HDR_LEN + cbcbytes,
desc.iv, pages, 1);
if (err) {
err = GSS_S_FAILURE;
goto out_err;
}
/* Now update buf to account for HMAC */
buf->tail[0].iov_len += kctx->gk5e->cksumlength;
buf->len += kctx->gk5e->cksumlength;
out_err:
if (err)
err = GSS_S_FAILURE;
return err;
}
u32
gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,
u32 *headskip, u32 *tailskip)
{
struct xdr_buf subbuf;
u32 ret = 0;
u8 *cksum_key;
struct crypto_blkcipher *cipher, *aux_cipher;
struct xdr_netobj our_hmac_obj;
u8 our_hmac[GSS_KRB5_MAX_CKSUM_LEN];
u8 pkt_hmac[GSS_KRB5_MAX_CKSUM_LEN];
int nblocks, blocksize, cbcbytes;
struct decryptor_desc desc;
unsigned int usage;
if (kctx->initiate) {
cipher = kctx->acceptor_enc;
aux_cipher = kctx->acceptor_enc_aux;
cksum_key = kctx->acceptor_integ;
usage = KG_USAGE_ACCEPTOR_SEAL;
} else {
cipher = kctx->initiator_enc;
aux_cipher = kctx->initiator_enc_aux;
cksum_key = kctx->initiator_integ;
usage = KG_USAGE_INITIATOR_SEAL;
}
blocksize = crypto_blkcipher_blocksize(cipher);
/* create a segment skipping the header and leaving out the checksum */
xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN,
(buf->len - offset - GSS_KRB5_TOK_HDR_LEN -
kctx->gk5e->cksumlength));
nblocks = (subbuf.len + blocksize - 1) / blocksize;
cbcbytes = 0;
if (nblocks > 2)
cbcbytes = (nblocks - 2) * blocksize;
memset(desc.iv, 0, sizeof(desc.iv));
if (cbcbytes) {
desc.fragno = 0;
desc.fraglen = 0;
desc.desc.info = desc.iv;
desc.desc.flags = 0;
desc.desc.tfm = aux_cipher;
sg_init_table(desc.frags, 4);
ret = xdr_process_buf(&subbuf, 0, cbcbytes, decryptor, &desc);
if (ret)
goto out_err;
}
/* Make sure IV carries forward from any CBC results. */
ret = gss_krb5_cts_crypt(cipher, &subbuf, cbcbytes, desc.iv, NULL, 0);
if (ret)
goto out_err;
/* Calculate our hmac over the plaintext data */
our_hmac_obj.len = sizeof(our_hmac);
our_hmac_obj.data = our_hmac;
ret = make_checksum_v2(kctx, NULL, 0, &subbuf, 0,
cksum_key, usage, &our_hmac_obj);
if (ret)
goto out_err;
/* Get the packet's hmac value */
ret = read_bytes_from_xdr_buf(buf, buf->len - kctx->gk5e->cksumlength,
pkt_hmac, kctx->gk5e->cksumlength);
if (ret)
goto out_err;
if (memcmp(pkt_hmac, our_hmac, kctx->gk5e->cksumlength) != 0) {
ret = GSS_S_BAD_SIG;
goto out_err;
}
*headskip = kctx->gk5e->conflen;
*tailskip = kctx->gk5e->cksumlength;
out_err:
if (ret && ret != GSS_S_BAD_SIG)
ret = GSS_S_FAILURE;
return ret;
}
/*
* Compute Kseq given the initial session key and the checksum.
* Set the key of the given cipher.
*/
int
krb5_rc4_setup_seq_key(struct krb5_ctx *kctx, struct crypto_blkcipher *cipher,
unsigned char *cksum)
{
struct crypto_hash *hmac;
struct hash_desc desc;
struct scatterlist sg[1];
u8 Kseq[GSS_KRB5_MAX_KEYLEN];
u32 zeroconstant = 0;
int err;
dprintk("%s: entered\n", __func__);
hmac = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(hmac)) {
dprintk("%s: error %ld, allocating hash '%s'\n",
__func__, PTR_ERR(hmac), kctx->gk5e->cksum_name);
return PTR_ERR(hmac);
}
desc.tfm = hmac;
desc.flags = 0;
err = crypto_hash_init(&desc);
if (err)
goto out_err;
/* Compute intermediate Kseq from session key */
err = crypto_hash_setkey(hmac, kctx->Ksess, kctx->gk5e->keylength);
if (err)
goto out_err;
sg_init_table(sg, 1);
sg_set_buf(sg, &zeroconstant, 4);
err = crypto_hash_digest(&desc, sg, 4, Kseq);
if (err)
goto out_err;
/* Compute final Kseq from the checksum and intermediate Kseq */
err = crypto_hash_setkey(hmac, Kseq, kctx->gk5e->keylength);
if (err)
goto out_err;
sg_set_buf(sg, cksum, 8);
err = crypto_hash_digest(&desc, sg, 8, Kseq);
if (err)
goto out_err;
err = crypto_blkcipher_setkey(cipher, Kseq, kctx->gk5e->keylength);
if (err)
goto out_err;
err = 0;
out_err:
crypto_free_hash(hmac);
dprintk("%s: returning %d\n", __func__, err);
return err;
}
/*
* Compute Kcrypt given the initial session key and the plaintext seqnum.
* Set the key of cipher kctx->enc.
*/
int
krb5_rc4_setup_enc_key(struct krb5_ctx *kctx, struct crypto_blkcipher *cipher,
s32 seqnum)
{
struct crypto_hash *hmac;
struct hash_desc desc;
struct scatterlist sg[1];
u8 Kcrypt[GSS_KRB5_MAX_KEYLEN];
u8 zeroconstant[4] = {0};
u8 seqnumarray[4];
int err, i;
dprintk("%s: entered, seqnum %u\n", __func__, seqnum);
hmac = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(hmac)) {
dprintk("%s: error %ld, allocating hash '%s'\n",
__func__, PTR_ERR(hmac), kctx->gk5e->cksum_name);
return PTR_ERR(hmac);
}
desc.tfm = hmac;
desc.flags = 0;
err = crypto_hash_init(&desc);
if (err)
goto out_err;
/* Compute intermediate Kcrypt from session key */
for (i = 0; i < kctx->gk5e->keylength; i++)
Kcrypt[i] = kctx->Ksess[i] ^ 0xf0;
err = crypto_hash_setkey(hmac, Kcrypt, kctx->gk5e->keylength);
if (err)
goto out_err;
sg_init_table(sg, 1);
sg_set_buf(sg, zeroconstant, 4);
err = crypto_hash_digest(&desc, sg, 4, Kcrypt);
if (err)
goto out_err;
/* Compute final Kcrypt from the seqnum and intermediate Kcrypt */
err = crypto_hash_setkey(hmac, Kcrypt, kctx->gk5e->keylength);
if (err)
goto out_err;
seqnumarray[0] = (unsigned char) ((seqnum >> 24) & 0xff);
seqnumarray[1] = (unsigned char) ((seqnum >> 16) & 0xff);
seqnumarray[2] = (unsigned char) ((seqnum >> 8) & 0xff);
seqnumarray[3] = (unsigned char) ((seqnum >> 0) & 0xff);
sg_set_buf(sg, seqnumarray, 4);
err = crypto_hash_digest(&desc, sg, 4, Kcrypt);
if (err)
goto out_err;
err = crypto_blkcipher_setkey(cipher, Kcrypt, kctx->gk5e->keylength);
if (err)
goto out_err;
err = 0;
out_err:
crypto_free_hash(hmac);
dprintk("%s: returning %d\n", __func__, err);
return err;
}